Primarily when it comes to gaming, we think of large role-playing games like "kizi" on http://www.kizifan.com/ or first-person shooters like "Destiny" or "Halo,", but just counting these this ignores the biggest market for games. So-called "casual" gamers by far make up the largest sector of those who play, and more often than not they do so on their mobile device.
According to Statista, in July 2017, iOS had over 783,000 games available on the App Store. This is a stunning amount of titles.
Apple's new frameworks for porting over iOS applications to the Mac might be a big deal for gamers. This probably won't help with huge AAA titles, but popular ones such as "Alto's Adventure," "Clash of Clans," and the like.
If this proves to be effective, it could encourage larger-scale mobile developers to give the Mac a second look, at least for more casual titles.